According to the law of , there is an inverse relationship between price and quantity demanded. that is, the demand curve for goods and services slopes downward. why? a. when the price of a good increases, consumers purchase complementary goods that are now relatively less expensive. b. when price increases, quantity demanded increases. c. when the price of a good increases, consumers' purchasing power falls, and they cannot buy as much of the good as they did prior to the price change. d. a and c only.